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Croitoru G, Jipa F, Greculeasa M, Broasca A, Voicu F, Gheorghe L, Pavel N. Buried Depressed-Cladding Waveguides Inscribed in Nd 3+ and Yb 3+ Doped CLNGG Laser Crystals by Picosecond-Laser Beam Writing. MATERIALS (BASEL, SWITZERLAND) 2024; 17:1758. [PMID: 38673115 PMCID: PMC11051540 DOI: 10.3390/ma17081758] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/29/2024] [Revised: 03/26/2024] [Accepted: 04/08/2024] [Indexed: 04/28/2024]
Abstract
Buried depressed-cladding waveguides were fabricated in 0.7-at.% Nd:Ca3Li0.275Nb1.775Ga2.95O12 (Nd:CLNGG) and 7.28-at.% Yb:CLNGG disordered laser crystals grown by Czochralski method. Circular waveguides with 100 μm diameters were inscribed in both crystals with picosecond (ps) laser pulses at 532 nm of 0.15 μJ energy at 500 kHz repetition rate. A line-by-line writing technique at 1 mm/s scanning speed was used. Laser emission at 1.06 μm (with 0.35 mJ pulse energy) and at 1.03 μm (with 0.16 mJ pulse energy) was obtained from the waveguide inscribed in Nd:CLNGG and Yb:CLNGG, respectively, employing quasi-continuous wave pumping with fiber-coupled diode lasers. The waveguide realized in RE3+-doped CLNGG crystals using ps-laser pulses at high repetition rates could provide Q-switched or mode-locked miniaturized lasers for a large number of photonic applications.
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Affiliation(s)
- Gabriela Croitoru
- Laboratory of Solid-State Quantum Electronics, National Institute for Laser, Plasma and Radiation Physics, 077125 Magurele, Ilfov, Romania; (M.G.); (A.B.); (F.V.); (L.G.); (N.P.)
| | - Florin Jipa
- Photonic Investigations Laboratory—PhIL, Center for Advanced Laser Technology, National Institute for Laser, Plasma and Radiation Physics, 077125 Magurele, Ilfov, Romania;
| | - Madalin Greculeasa
- Laboratory of Solid-State Quantum Electronics, National Institute for Laser, Plasma and Radiation Physics, 077125 Magurele, Ilfov, Romania; (M.G.); (A.B.); (F.V.); (L.G.); (N.P.)
| | - Alin Broasca
- Laboratory of Solid-State Quantum Electronics, National Institute for Laser, Plasma and Radiation Physics, 077125 Magurele, Ilfov, Romania; (M.G.); (A.B.); (F.V.); (L.G.); (N.P.)
| | - Flavius Voicu
- Laboratory of Solid-State Quantum Electronics, National Institute for Laser, Plasma and Radiation Physics, 077125 Magurele, Ilfov, Romania; (M.G.); (A.B.); (F.V.); (L.G.); (N.P.)
| | - Lucian Gheorghe
- Laboratory of Solid-State Quantum Electronics, National Institute for Laser, Plasma and Radiation Physics, 077125 Magurele, Ilfov, Romania; (M.G.); (A.B.); (F.V.); (L.G.); (N.P.)
| | - Nicolaie Pavel
- Laboratory of Solid-State Quantum Electronics, National Institute for Laser, Plasma and Radiation Physics, 077125 Magurele, Ilfov, Romania; (M.G.); (A.B.); (F.V.); (L.G.); (N.P.)
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Lv H, Chu L, Wang S, Sun S, Sun X, Jia Y, Chen F. Layer-dependent nonlinear optical properties of two-dimensional InSe and its applications in waveguide lasers. OPTICS EXPRESS 2022; 30:23986-23999. [PMID: 36225069 DOI: 10.1364/oe.462811] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Accepted: 06/06/2022] [Indexed: 06/16/2023]
Abstract
The thickness-dependent third-order nonlinear optical properties of two-dimensional β-InSe and its potential applications as a saturable absorber in pulsed laser generation are investigated. InSe sheets with different layers are prepared by the chemical vapor deposition. Using open-aperture femtosecond Z-scan technique at 1030 nm, the modulation depth and nonlinear absorption coefficient are obtained to be 36% and -1.6 × 104 cm·GW-1, respectively. The intrinsic mechanism of the layer-dependent energy band structure evolution is analyzed based on density functional theory, and the theoretical analysis is consistent with the experimental results. Based on a waveguide cavity, a Q-switched mode-locked laser at 1 µm with a repetition frequency of 8.51 GHz and a pulse duration of 28 ps is achieved by utilizing the layered InSe as a saturable absorber. This work provides an in-depth understanding of layer-dependent properties of InSe and extends its applications in laser technology for compact light devices.
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Sun X, Sun S, Romero C, Vázquez de Aldana JR, Liu F, Jia Y, Chen F. Femtosecond laser direct writing of depressed cladding waveguides in Nd:YAG with "ear-like" structures: fabrication and laser generation. OPTICS EXPRESS 2021; 29:4296-4307. [PMID: 33771012 DOI: 10.1364/oe.417815] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Accepted: 01/20/2021] [Indexed: 06/12/2023]
Abstract
Low-loss depressed cladding waveguide architecture is highly attractive for improving the laser performance of waveguide lasers. We report on the design and fabrication of the "ear-like" waveguide structures formed by a set of parallel tracks in neodymium-doped yttrium aluminum garnet (Nd:YAG) crystal via femtosecond laser writing. The obtained "ear-like" waveguides are with more symmetric mode profiles and lower losses by systematically comparing the guiding properties of two kinds of normal cladding waveguide. Efficient waveguide lasers are realized based on the designed structure in both continuous wave and pulsed regimes. Combined the high-gain from cladding waveguide and special "ear-like" structure, a passively fundamentally Q-switched laser with the narrow pulse width and the high repetition rate has been obtained by using tin diselenide (SnSe2) as saturable absorber.
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Jia Y, He R, Vázquez de Aldana JR, Liu H, Chen F. Femtosecond laser direct writing of few-mode depressed-cladding waveguide lasers. OPTICS EXPRESS 2019; 27:30941-30951. [PMID: 31684335 DOI: 10.1364/oe.27.030941] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Accepted: 09/26/2019] [Indexed: 06/10/2023]
Abstract
We report on mirrorless laser operation of Nd:YVO4 single- and double-cladding waveguides fabricated by femtosecond laser direct writing. Fundamental- (LP01) and high-order-mode (LP03, LP05) guiding and lasing have been observed in waveguides with different geometries and sizes. Double-cladding waveguides exhibit good guiding and lasing performance via inheriting advantages respectively from individual single cladding. As a result, continuous-wave lasing with a threshold as low as 59 mW is obtained, depending on the optical feedback provided only by Fresnel reflections at the waveguide end faces. By using few-layer graphene as saturable absorber, passively Q-switched operation in fabricated waveguides is also achieved.
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Passive Q-Switching by Cr 4+:YAG Saturable Absorber of Buried Depressed-Cladding Waveguides Obtained in Nd-Doped Media by Femtosecond Laser Beam Writing. MATERIALS 2018; 11:ma11091689. [PMID: 30213047 PMCID: PMC6165094 DOI: 10.3390/ma11091689] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/18/2018] [Revised: 09/09/2018] [Accepted: 09/10/2018] [Indexed: 01/02/2023]
Abstract
We report on laser performances obtained in Q-switch mode operation from buried depressed-cladding waveguides of circular shape (100 μm diameter) that were inscribed in Nd:YAG and Nd:YVO4 media by direct writing with a femtosecond laser beam. The Q-switch operation was realized with a Cr4+:YAG saturable absorber, aiming to obtain laser pulses of moderate (few μJ) energy at high (tens to hundreds kHz) repetition rate. An average power of 0.52 W at 1.06 μm consisting of a train of pulses of 7.79 μJ energy at 67 kHz repetition rate, was obtained from a waveguide realized in a 4.8 mm long, 1.1-at % Nd:YAG ceramics; the pulse peak power reached 1.95 kW. A similar waveguide that was inscribed in a 3.4 mm long, 1.0-at % Nd:YVO4 crystal yielded laser pulses with 9.4 μJ energy at 83 kHz repetition rate (at 0.77 W average power) and 1.36 kW peak power. The laser performances obtained in continuous-wave operation were discussed for each waveguide used in the experiments. Thus, a continuous-wave output power of 1.45 W was obtained from the circular buried depressed-cladding waveguide inscribed in the 1.1-at %, 4.8 mm long Nd:YAG; the overall optical-to-optical efficiency, with respect to the absorbed pump power, was 0.21. The waveguide inscribed in the 1.0-at %, 3.4 mm long Nd:YVO4 crystal yielded 1.85 W power at 0.26 overall optical efficiency. This work shows the possibility to build compact laser systems with average-to-high peak power pulses based on waveguides realized by a femtosecond (fs) laser beam direct writing technique and that are pumped by a fiber-coupled diode laser.
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Room-temperature subnanosecond waveguide lasers in Nd:YVO 4 Q-switched by phase-change VO 2: A comparison with 2D materials. Sci Rep 2017; 7:46162. [PMID: 28383017 PMCID: PMC5382777 DOI: 10.1038/srep46162] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Accepted: 03/08/2017] [Indexed: 12/01/2022] Open
Abstract
We report on room-temperature subnanosecond waveguide laser operation at 1064 nm in a Nd:YVO4 crystal waveguide through Q-switching of phase-change nanomaterial vanadium dioxide (VO2). The unique feature of VO2 nanomaterial from the insulating to metallic phases offers low-saturation-intensity nonlinear absorptions of light for subnanosecond pulse generation. The low-loss waveguide is fabricated by using the femtosecond laser writing with depressed cladding geometry. Under optical pump at 808 nm, efficient pulsed laser has been achieved in the Nd:YVO4 waveguide, reaching minimum pulse duration of 690 ps and maximum output average power of 66.7 mW. To compare the Q-switched laser performances by VO2 saturable absorber with those based on two-dimensional materials, the 1064-nm laser pulses have been realized in the same waveguide platform with either graphene or transition metal dichalcogenide (in this work, WS2) coated mirror. The results on 2D material Q-switched waveguide lasers have shown that the shortest pulses are with 22-ns duration, whilst the maximum output average powers reach ~161.9 mW. This work shows the obvious difference on the lasing properties based on phase-change material and 2D materials, and suggests potential applications of VO2 as low-cost saturable absorber for subnanosecond laser generation.
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Huang KY, Su CK, Lin MW, Chiu YC, Huang YC. Efficient 750-nm LED-pumped Nd:YAG laser. OPTICS EXPRESS 2016; 24:12043-12054. [PMID: 27410125 DOI: 10.1364/oe.24.012043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We report an Nd:YAG laser pumped by light emission diodes (LEDs) at 750 nm. With 1% output coupling from a linear cavity containing a 2-cm long Nd:YAG crystal, the laser generated 37.5 μJ pulse energy at 1064 nm with M2 = 1.1 when pumped by 2.73-mJ LED energy in a 1-ms pulse at a 10 Hz rate. The measured optical and slope efficiencies for this linear-cavity laser are 1.36, and 9%, respectively. With 1 and 5% output couplings from a Z-cavity containing the same laser crystal, the lasers generated 346 and 288 μJ pulse energy with an optical efficiency of 3.4 and 2.8% and slope efficiency of 6.6 and 14%, respectively, for the same 1-ms pump pulse repeating at a 10 Hz rate. At the highest output from the Z-cavity, the measured M2 for the beam is 3.6.
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Nie W, Jia Y, Vázquez de Aldana JR, Chen F. Efficient Second Harmonic Generation in 3D Nonlinear Optical-Lattice-Like Cladding Waveguide Splitters by Femtosecond Laser Inscription. Sci Rep 2016; 6:22310. [PMID: 26924255 PMCID: PMC4770408 DOI: 10.1038/srep22310] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Accepted: 02/09/2016] [Indexed: 11/09/2022] Open
Abstract
Integrated photonic devices with beam splitting function are intriguing for a broad range of photonic applications. Through optical-lattice-like cladding waveguide structures fabricated by direct femtosecond laser writing, the light propagation can be engineered via the track-confined refractive index profiles, achieving tailored output beam distributions. In this work, we report on the fabrication of 3D laser-written optical-lattice-like structures in a nonlinear KTP crystal to implement 1 × 4 beam splitting. Second harmonic generation (SHG) of green light through these nonlinear waveguide beam splitter structures provides the capability for the compact visible laser emitting devices. With Type II phase matching of the fundamental wavelength (@ 1064 nm) to second harmonic waves (@ 532 nm), the frequency doubling has been achieved through this three-dimensional beam splitter. Under 1064-nm continuous-wave fundamental-wavelength pump beam, guided-wave SHG at 532 nm are measured with the maximum power of 0.65 mW and 0.48 mW for waveguide splitters (0.67 mW and 0.51 mW for corresponding straight channel waveguides), corresponding to a SH conversion efficiency of approximately ~14.3%/W and 13.9%/W (11.2%/W, 11.3%/W for corresponding straight channel waveguides), respectively. This work paves a way to fabricate compact integrated nonlinear photonic devices in a single chip with beam dividing functions.
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Affiliation(s)
- Weijie Nie
- School of Physics, State Key Laboratory of Crystal Materials, and Key Laboratory of Particle Physics and Particle Irradiation (Ministry of Education), Shandong University, 250100 Jinan, Shandong, China
| | - Yuechen Jia
- Laboratory for Optical Systems, Department of Microsystems Engineering-IMTEK, University of Freiburg, 79110 Freiburg, Germany
| | | | - Feng Chen
- School of Physics, State Key Laboratory of Crystal Materials, and Key Laboratory of Particle Physics and Particle Irradiation (Ministry of Education), Shandong University, 250100 Jinan, Shandong, China
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Tan Y, Guo Z, Ma L, Zhang H, Akhmadaliev S, Zhou S, Chen F. Q-switched waveguide laser based on two-dimensional semiconducting materials: tungsten disulfide and black phosphorous. OPTICS EXPRESS 2016; 24:2858-2866. [PMID: 26906854 DOI: 10.1364/oe.24.002858] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Owing to their unique properties, graphene-like two dimensional semiconducting materials, including Tungsten Disulfide (WS2) and Black Phosphorous (BP), have attracted increasing interest from basic research to practical applications. Herein, we demonstrated the ultrafast nonlinear saturable absorption response of WS2 and BP films in the waveguide structure. Through fabricating WS2 and BP films by evaporating the solutions on glass wafers. Saturable absorber films were attached onto the end-facet of the waveguide, which therefore constitutes a resonant cavity for the waveguide laser. Under a pump laser at 810 nm, we could obtain a stable Q-switched operation in the waveguide structure. This work indicated the significant potential of WS2 and BP for the ultrafast waveguide laser.
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Nie W, Cheng C, Jia Y, Romero C, Vázquez de Aldana JR, Chen F. Dual-wavelength waveguide lasers at 1064 and 1079 nm in Nd:YAP crystal by direct femtosecond laser writing. OPTICS LETTERS 2015; 40:2437-2440. [PMID: 26393759 DOI: 10.1364/ol.40.002437] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Low-loss depressed cladding waveguides have been produced in Nd:YAP laser crystal by using direct femtosecond laser writing. Under optical pump at 812 nm at room temperature, continuous-wave simultaneous dual-wavelength laser oscillations at 1064 and 1079 nm, both along TM polarization, have been realized in the waveguiding structures. It has been found that, with the variation of pump polarization, the intensity ratio of 1064 and 1079 nm emissions varies periodically, while the polarization of output dual-wavelength laser remains unchanged. The maximum output power achieved for the Nd:YAP waveguide lasers is ∼200 mW with a slope efficiency of 33.4%.
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He R, Hernández-Palmero I, Romero C, Vázquez de Aldana JR, Chen F. Three-dimensional dielectric crystalline waveguide beam splitters in mid-infrared band by direct femtosecond laser writing. OPTICS EXPRESS 2014; 22:31293-31298. [PMID: 25607077 DOI: 10.1364/oe.22.031293] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We report on the fabrication of three-dimensional waveguide beam splitters in a dielectric Bi(4)Ge(3)O(12) (BGO) crystal by direct femtosecond laser writing. In the laser written tracks of BGO crystal, positive refractive index is induced, resulting in so-called Type I configuration waveguiding cores. The "multiscan" technique is utilized to shape cores with designed cross-sectional geometry in order to achieve guidance at mid-infrared wavelength of 4 μm. The fundamental mode guidance along both TE and TM polarizations has been obtained in the waveguide structures. With this feature, we implement beam splitters from 2D to 3D geometries, and realize 1 × 2, 1 × 3, and 1 × 4 power splitting at 4μm.
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